Can anyone tell if the rear Grimeca Hub has a cush drive in it that is fitted to the Harris Matchless,

I have just completed a 2 year rebuild of my Harris and have done 440 miles on it in the last 2 months, i have noticed the rear chain seems to need adjusting already is this a commen thing on these bikes?

Hope someone can advise, if you look in this months Realclassic mag in the letters page you will see a picture of it.

440 miles would be about right to check the chain after fitting a new one. I would expect to find it had slackened a bit. A little stretch and now pulled real tight against the adjusters. Just re adjust it and check again after another 4/500 miles.

If you're still watching I can confirm that Harris G80s are notoriously hard on chains and do a fair job of breaking spokes in the rear wheel too. IMHO the cush-drive in the rear hub is inadequate and this lack of flexibility also gives the primary drive gears a hard time. Expect to adjust your chain frequently but don't run it as tight as a "normal" bike or breakage may follow. Fitting a Scottoiler helps a lot, as does some sort of rain deflector valance fitted to the inside of the right hand swinging arm.

The situation isn't helped by a tendency to erratic running under 2500rpm which causes much snatching. Mike Keogh (who started Sportax) once told me on the 'phone that this was a fault within the original Dellorto carburettor spec. and no amount of jet changing or screw twiddling would fix it. He knew how to effect a cure but, unfortunately, it wasn't convenient for me to post him my carb at the time. Now it's too late - where are you Mike?

I guess you're referring to the new Hinkley Bonnevilles / Tiger 100s and not the Harris Bonnevilles, Rob?

I've had my Radiellis replaced with Morad/Akront rims, rebuilt by Derek Yorke of Anglia Wheels (used to be Essex Wheels before the schism). What a super job! Extra heavyweight stainless spokes and, when struck, they all still ring with the nearly the same note after several thousand hard miles.

You shouldn't expect spoke breakage on a (relatively) new bike though.

Try putting a Busmar double adult sidecar on a 1954 AJS 18S and then cornering hard for breaking spokes. On one particular journey returning from a Jampot Rally I told myself that I would stop if the number of sound spokes dropped below 30 (75% of the full compliment). About 5 miles from home I got down to 30 spokes and just made it home. Driving into the garage required a sharp right hand turn............. and the rear wheel immediately collapsed.

I sent Ian the diagram of the Grimeca hub to show the cush drive, but agree the the G80 (as built) is hard on spokes. With heavyweight spokes fitted and now a well-tuned Mikuni carb, I've had no further problem in the last eight years.